Devices for electrosurgery

ABSTRACT

Devices for electrosurgery by means of oxy-hydro combustion and methods for use of such devices in electrosurgical procedures. Provided are devices for combustion of oxygen and hydrogen, or other hydrocarbon fuels, wherein oxygen and hydrogen may be generated by electrolysis or oxygen and hydrogen, or other hydrocarbon fuels, may be supplied, such devices including an ignition source and an adjustable and translatable sheath for controlling such reactions. Also provided is a detachable and positionable sheath for controlling reactions and minimizing tissue damage with conventional electrosurgery devices.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent Ser. No.11/061,397, entitled Devices for Electrosurgery, filed on Feb. 17, 2005,issued as U.S. Pat. No. 7,445,619 on Nov. 4, 2008, which is acontinuation-in-part application of U.S. patent application Ser. No.10/486,739, entitled Methods and Devices for Electrosurgery, filed onAug. 24, 2004 now abandoned, which in turn was a national stage entrypursuant to 35 U.S.C. §371 of International Application Serial No.PCT/US02/26277, entitled Methods and Devices for Electrosurgery, filedon Aug. 15, 2002, which claimed priority to U.S. Provisional PatentApplication Ser. No. 60/312,965, entitled System and Method ofElectrosurgical Biologic Tissue Modification and Treatment UtilizingOxy-Hydro Combustion—Acid Base Shift Reactions, filed on Aug. 15, 2001.

U.S. application Ser. No. 11/061,397 is a continuation-in-partapplication of U.S. application Ser. No. 10/119,671, entitled Methodsand Devices for Electrosurgery, filed on Apr. 9, 2002, issued as U.S.Pat. No. 6,902,564 on Jun. 7, 2005, which claimed priority to U.S.Provisional Application Ser. No. 60/312,965, entitled System and Methodof Electrosurgical Biologic Tissue Modification and Treatment UtilizingOxy-Hydro Combustion—Acid Base Shift Reactions, filed on Aug. 15, 2001.

U.S. application Ser. No. 11/061,397 is also a continuation-in-partapplication of U.S. application Ser. No. 11/010,174, entitled Methodsfor Electrosurgical Electrolysis, filed on Dec. 10, 2004, which in turnwas a continuation application of International Application Serial No.PCT/US03/18575, entitled Methods and Devices for ElectrosurgicalElectrolysis, filed on Jun. 10, 2003, which claimed priority to U.S.Provisional Patent Application Ser. No. 60/387,775, entitled Methods andDevices for Electrosurgical Electrolysis, filed on Jun. 10, 2002.

U.S. application Ser. No. 11/061,397 is a continuation-in-partapplication of U.S. application Ser. No. 11/006,079, entitled Methodsand Devices for Electrosurgery, filed on Dec. 6, 2004, which in turn wasa continuation-in-part application of International Application SerialNo. PCT/US03/18116, entitled Methods and Devices for Electrosurgery,filed on Jun. 6, 2003, which claimed priority to U.S. Provisional PatentApplication Ser. No. 60/387,114, entitled Methods and Devices forElectrosurgery, filed on Jun. 6, 2002, and to U.S. Provisional PatentApplication Ser. No. 60/387,775, entitled Methods and Devices forElectrosurgical Electrolysis, filed on Jun. 10, 2002.

U.S. application Ser. No. 11/061,397 is a continuation-in-partapplication of U.S. application Ser. No. 10/414,781, entitled Method ForAchieving Tissue Changes In Bone Or Bone-Derived Tissue, filed on Apr.15, 2003, issued as U.S. Pat. No. 7,105,011 on Sep. 12, 2006, which inturn was a divisional application of U.S. Pat. No. 6,547,794, entitledMethods for Fusing Bone During Endoscopy Procedures, issued on Apr. 15,2003, and filed as U.S. Ser. No. 09/885,749 on Jun. 19, 2001, whichclaimed priority to U.S. Provisional Patent Application Ser. No.60/226,370, entitled Method For Fusing Bone During Endoscopy Procedures,filed on Aug. 18, 2000, and of U.S. Provisional Patent Application Ser.No. 60/272,955, entitled Method For Fusing Bone During EndoscopyProcedures, filed on Mar. 2, 2001.

U.S. application Ser. No. 11/061,397 is a continuation-in-partapplication of U.S. application Ser. No. 10/741,753, entitled Methodsand Compositions for Fusing Bone During Endoscopy Procedures, filed onDec. 19, 2003, which in turn was a continuation application ofInternational Application No. PCT/US02/19498, International PublicationNo. WO 02/102438, entitled Methods and Compositions For Fusing BoneDuring Endoscopy Procedures, filed on Jun. 19, 2002, which in turn was acontinuation-in-part application of U.S. Pat. No. 6,547,794, entitledMethods for Fusing Bone During Endoscopy Procedures, issued on Apr. 15,2003, and filed as U.S. Ser. No. 09/885,749 on Jun. 19, 2001, whichclaimed priority to U.S. Provisional Patent Application Ser. No.60/226,370, entitled Method For Fusing Bone During Endoscopy Procedures,filed on Aug. 18, 2000, and of U.S. Provisional Patent Application Ser.No. 60/272,955, entitled Method For Fusing Bone During EndoscopyProcedures, filed on Mar. 2, 2001.

U.S. application Ser. No. 11/061,397 also claims the benefit of thefiling of U.S. Provisional Patent Application Ser. No. 60/545,097,entitled Devices for Electrosurgery, filed on Feb. 17, 2004. TheSpecification and claims thereof of each of the foregoing isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention (Technical Field)

The present invention relates to devices for electrosurgery, includingdevices that operate by means of oxygen and hydrogen combustion, andmethods utilizing such devices.

2. Description of Related Art

Note that the following discussion refers to a number of publications byauthor(s) and year of publication. Discussion of such publicationsherein is given for more complete background and is not to be construedas an admission that such publications are prior art for patentabilitydetermination purposes.

A variety of electrosurgical devices, used for cutting, ablation, andthe like in surgical procedures, are known. In general, it is claimedthat these devices utilize mechanisms of action based on various plasmaformation physiochemical paradigms. A plasma, broadly defined as “thefourth state of matter” as opposed to solids, liquids, and gases, is astate in which atoms have been broken down to form free electrons andstripped nuclei by the application of high energy or temperatures (ca.10⁶ degrees). In a plasma, the charge of the electrons is balanced bythe charge of the positive ions so that the system as a whole iselectrically neutral. The energy input required to initiate a plasma isrelated to the initial state of the matter as a solid, liquid, or gas,the molecular bond energy, and the ease with which electrons can bestripped from their orbits, among other variables. The percent of thesamples that actually become a plasma is usually very small due to thelarge energy requirements to create a plasma (i.e. ˜0.1% of a mole).Further, a plasma can be constrained by magnetic fields lowering theinput energy necessary. A sustainable plasma often requires a vacuum ormagnetic field control since the plasma elements quickly seek to begrounded, quenching the plasma; however, some systems may form shortduration plasmas on the order of nano- or micro-seconds depending uponenergy input and degree of vacuum/magnetic field present.

Some prior art references disclose electrosurgical devices with claimeduse of a gas plasma consisting of an ionized gas that is capable ofconducting electrical energy. In certain of these devices, eitherambient air or a supplied gas is used for ionization, such as thedevices disclosed in U.S. Pat. Nos. 5,669,904, 6,206,878 and 6,213,999.If a gas is supplied, it is an inert gas such as argon. In general,these devices are intended for use in ambient atmosphere for thetreatment of soft tissue.

Other electrosurgical devices function in liquid media and utilize someform of radiofrequency (RF) energy, such as with two or more electrodes.Heat is generated by use of the RF energy, resulting in destruction orablation of tissues in proximity to the electrodes. Thus the devices maybe employed for coagulation of blood vessels, tissue dissection, tissueremoval, and the like. U.S. Pat. No. 6,135,998 teaches anelectrosurgical probe immersed in liquid media or tissue, wherein anelectrical pulse is applied, with the claimed result that “plasmastreamers” are formed from the endface area of a first electrode. Inthis patent, it is claimed that cutting action results from the plasmastreamers. The minimum voltage is on the order of 1.5-2.0 kV, with 15 kVbeing the preferred maximum voltage, at a minimum power dissipation of500 Watts, and preferable a higher power dissipation of 800 to 1500Watts.

Other lower energy electrosurgical devices are known, consisting ofmonopolar and bipolar configurations that function at energyconfigurations at or below 1.4 kV and 300 Watts. Both monopolarelectrosurgical devices, in which the electrosurgical device includes anactive electrode with a return electrode separately connected to thepatient such that direct electric current flows through the patient'sbody, and bipolar electrosurgical devices, in which the electrosurgicaldevice includes both active and return electrodes, are now well known inthe art. These electrosurgical device configurations can be used inambient air or in a fluid medium. In general, it has been believed thatthese electrosurgical devices generally operate by means of creation ofa plasma or some related form of ionization. Thus prior art devices,such as that disclosed in U.S. Pat. No. 5,683,366, are claimed to relyon the fluid irrigant components participating in ionic excitation andrelaxation, with attendant release of photonic energy. This mode ofoperation is often referred to as “utilizing a plasma”. Prior artmethods claiming an ionized vapor layer or plasma include, in additionto the patents disclosed above, the methods disclosed in U.S. Pat. Nos.5,697,882, 6,149,620, 6,241,723, 6,264,652 and 6,322,549, among others.

A plasma requires that atoms be completely ionized to a gas of positiveions and electrons, and, if sustainable, would likely need to occur in avacuum-like environment. It is unlikely that many, if not most, priorart devices generate a plasma even for a short time. This most notablyfollows from consideration of the overall energy balance required toinitiate or sustain a plasma in either ambient air or aqueous, cellular,or other biologic environments. The nominal 200 to 1500 Watts of powernormally employed in a typical electrosurgical device, or any otherenergy level or configuration contemplated for electrosurgicalapplication (most, however, are between 200 and 300 Watts), isinsufficient to initiate and/or sustain a plasma, even in a vacuum andwith magnetic field control, even for a short period of time. Forexample, in a saline solution typically utilized during electrosurgery,49.6 kW-s/mole (I eV=5.13908; II eV=47.2864; III eV=71.6200; etc.) isneeded to ionize sodium, while the ionization energy of simple water is12.6206 eV (i.e. one electron volt=1.602177×10⁻¹⁹ Joules) as referencedin CRC Handbook of Chemistry and Physics, 72 ed., Lide, David R., CRCPress, 1991. The energy to initiate a plasma typically exceeds theionization potential of a material, and to sustain a plasma requires aneven greater energy input. Further, once ions have been formed insolution, such as in an aqueous solution of sodium as employed inelectrosurgery, a yet even greater energy input is required.

Further, many prior art electrosurgical references ignore recognizedphenomena relating to plasmas, such as the large ionization potentialsand energy necessary to initiate a plasma or to sustain a plasma and therole of the vacuum or magnetic fields in such circumstances. Mostelectrosurgical devices cannot deliver the energy required to initiate,let alone sustain, a plasma; and, further, electrosurgical applicationsdo not occur in a vacuum environment or in a magnetically controlledenvironment. The energy needed to create a plasma in vivo duringelectrosurgery would overwhelm the ability of the host organism towithstand such an energy insult globally. Plasma cutters as used inmetal fabrication are examples of the high energy necessary to “utilizea plasma” at normal pressures; yet such high energy levels certainlyhave not been contemplated for electrosurgical application due to thesignificant iatrogenic damage that would occur. This understanding hasled us to search for other physiochemical paradigms to understandelectrosurgery as it is practiced at energy configurations amenable andsafe for in vivo application and to more fully and correctly explaincommon physiochemical observations during electrosurgery in order tocreate more appropriate electrosurgical devices and methods.

In industrial settings, it is known to employ an oxygen and hydrogencombustion reaction, such that a “water torch” results by ignition ofco-mingled oxygen and hydrogen gas molecules liberated from waterthrough high frequency electrolysis, as is disclosed in U.S. Pat. No.4,014,777. However, such methods have never been intentionally appliedto medical procedures, such as for electrosurgical devices and methods.Further, such devices and methods have never been optimized for theconstraints of use of electrosurgical devices on biologic tissue,including constraints resulting from the presence of discrete quantitiesof electrolyte fluids, the presence of physiologic fluids and materials,the desires to minimize collateral tissue injury, the need to avoidgeneration of toxic by-products, the attendant host organism tissueresponse, and the like.

There is thus a need for electrosurgical devices that are optimized tothe true physical and chemical processes involved in the operation anduse of such electrosurgical devices upon biologic tissue within thisenergy spectrum and power range.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, the invention provides an apparatus forelectrosurgery, the apparatus including a probe with a distal end and aproximal end, the proximal end forming a handle for holding the probe;first and second gas delivery channels disposed within probe; a gasmixing plenum chamber with an inlet and an outlet at the distal end ofthe probe, the first and second gas delivery channels being in fluidconnection with the inlet; an ignition source proximal to the gas mixingplenum chamber outlet; a cylindrical sleeve positioned around the distalend of the probe; and, an adjustably positionable actuator disposed onthe handle and translatably connected to the cylindrical sleeve, suchthat the cylindrical sleeve can be longitudinally translated relative tothe distal end of the probe, thereby forming a cavity of variable volumeabout the distal end of the probe. The ignition source may include anactive electrode, which may optionally be battery powered, and whichserves to initiate combination of the first and second gases. In theembodiment wherein the ignition source includes an active electrode, thecylindrical sleeve may be an electrically insulating sleeve, optionallywherein the cylindrical sleeve extends distally beyond the activeelectrode, such as extending distally between about 1 mm and about 40 mmbeyond the active electrode. Further in the embodiment wherein theignition source includes an active electrode, the apparatus can includeat least one return electrode.

The apparatus may further include least one detector proximal to thedistal end of the probe and within the cavity of variable volume fordetecting a parameter relating to oxy-hydro combustion. Such detectormay detect one or more of pH concentration, temperature, conductivity,ionic concentration, consumption of oxygen or hydrogen, sound, orchanges in local pressure. The apparatus can thus further include adetection circuit for receiving a parameter detected by the at least onedetector.

Where the ignition source includes an active electrode, the apparatuscan further include a control circuit providing an output control signalcontrolling an amount of power output to the at least one activeelectrode in response to an output from a detection circuit forreceiving a parameter detected by at least one detector disposedproximal to the distal end of the probe and within the cavity ofvariable volume for detecting a parameter relating to oxy-hydrocombustion.

In the apparatus there can further be provided a self-regulating thermalquenching portal system comprising at least one opening for introducingan aqueous fluid to gas mixing plenum chamber. In yet anotherembodiment, there can be provided a flame arrester positioned betweenthe gas mixing plenum chamber outlet and the active electrode.

In another embodiment, the invention provides a movable sheath adaptedfor use with a conventional radiofrequency (RF) electrosurgical probe,the sheath including a generally cylindrical plenum with an open firstend and an open second end and of a diameter such that the open secondend may be co-axially placed over the electrode end of an RF electricalprobe, whereby the open first end extends beyond the electrode end ofthe RF electrical probe; and a flexible polymeric fixation sleeve forsecuring the position of the generally cylindrical plenum to the RFelectrosurgical probe. In one embodiment of the sheath, the generallycylindrical plenum includes a plurality of perforations. The flexiblepolymeric fixation sleeve of the sheath can be fixed to the generallycylindrical plenum, and the flexible polymeric fixation sleeve caninclude a plurality of demarcations for determining the position of themovable sheath with respect to the electrode end of the RF electricalprobe.

In yet another embodiment, there is provided an apparatus forelectrosurgery including a probe with a distal end and a proximal end; aconcave plenum chamber on the distal end of the probe with an activeelectrode disposed therein, the active electrode providing forelectrolysis of an aqueous medium into hydrogen and oxygen and ignitionof such hydrogen and oxygen; and a circumferential insulated leadingedge on the concave plenum chamber on the distal end of the probe forsealing contact with tissue to be treated. The leading edge can includea sharpened edge for sealing contact with tissue, or alternatively aroughened edge for sealing contact with tissue. The apparatus canfurther include a return electrode on the proximal side of thecircumferential insulated leading edge and disposed on an exteriorsurface of the probe.

A primary object of the present invention is to provide anelectrosurgical device that regulates the rate of combustion inunderwater environments, such as combustion in aqueous, cellular andbiologic environments.

Another object of the present invention is to provide an electrosurgicaldevice that provides tissue dissection, ablation and the like by meansof an oxy-hydro combustion reaction.

Another object of the present invention is to provide a device andmethods that eliminate the need for use of an ionic solution, such assaline, to foster oxy-hydro combustion reactions at the surgical site.

Another object of the present invention is to provide for oxy-hydrocombustion that utilizes the salt ion fluid of intra-cellularstructures.

Another object of the present invention is to provide devices employinglow energy levels to achieve ignition of oxygen and hydrogen gases, suchignition and subsequent combustion providing the desired tissuedissection, ablation and the like.

Another object of the present invention is to provide an electrosurgicaldevice with lower energy requirements, thereby resulting in a lower netenergy transfer to local tissue structures, whereby there are lowerlevels of collateral tissue damage.

Another object of the present invention is to provide an electrosurgicaldevice that provides combustion gases, such as oxygen and hydrogen, aspart of the electrosurgical device.

Another object of the present invention is to provide an electrosurgicaldevice that provides oxygen and hydrogen combustion gases by hydrolysis,with ignition of the resulting combustion gases, with the plenum furtherincluding a sharp-edged plenum chamber leading edge to enhance contactof the plenum to tissue and prevent contact of tissue with the zone ofoxygen and hydrogen combustion.

Another object of the present invention is to provide an electrosurgicaldevice that provides for combustion of gases, such as oxygen andhydrogen, and further includes one or more portals to draw in ambientfluid to partially quench the combustion reaction, thereby reducing thenet heat of reaction and additionally reducing the thermal requirementsof the flame ejection nozzle.

Another object of the present invention is to provide an electrosurgicaldevice that can operate on either alternating current (AC) or directcurrent (DC), and that does not require an unequal current density as adistinguishing feature between a first electrode and a second electrode.

A primary advantage of the present invention is the ability to optimizeionic salt solutions for the oxy-hydro combustion reaction.

Another advantage of the present invention is the utilization of anacid-base throttle effect to regulate an electrosurgical device.

Another advantage of the present invention is the use of a wide range ofdifferent and novel salt solutions, in addition to the normal salineconventionally employed in electrosurgical procedures.

Another advantage of the present invention is that devices and methodsare provided that do not require an unequal current density between afirst electrode and second electrode, and may effectively operate withequal current densities, optionally for electrolysis of an aqueousmedium into oxygen and hydrogen, and additionally for initiation ofcombustion of oxygen and hydrogen, where the oxygen and hydrogen isgenerated by electrolysis or is externally provided.

Another advantage of the present invention is that devices and methodsare provided that require lower energy levels and further lower currentdensities than do prior art electrosurgical devices, such energy levelsand current densities being only such as are required to initiatecombustion of oxygen and hydrogen (or a hydrocarbon gas) and optionallyfor electrolysis of an aqueous medium into oxygen and hydrogen.

Another advantage of the present invention is that it provides for theuse of feedback loop control algorithms to govern electrical motors orother actuating means to position the movable insulating sheath member,in response to the degree of electrolysis or combustion desired.

Other objects, advantages and novel features, and further scope ofapplicability of the present invention will be set forth in part in thedetailed description to follow, taken in conjunction with theaccompanying drawings, and in part will become apparent to those skilledin the art upon examination of the following, or may be learned bypractice of the invention. The objects and advantages of the inventionmay be realized and attained by means of the instrumentalities andcombinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a partof the specification, illustrate one or more embodiments of the presentinvention and, together with the description, serve to explain theprinciples of the invention. The drawings are only for the purpose ofillustrating one or more preferred embodiments of the invention and arenot to be construed as limiting the invention. In the drawings:

FIG. 1A is the stoichiometric chemical equation for chemical reactionsrelated to the invention;

FIG. 1B is the equation for the acid-base “throttle” effect;

FIG. 1C is the equation for a generalized form of the oxy-hydro reactionprocess;

FIG. 1D is the equation for a generalized form of the oxy-hydro reactionprocess showing the effect of varying molar coefficients;

FIG. 2 is a view of an electrosurgical probe with a retractable sheathto create a fluid chamber that activates the acid-base throttle effectof oxy-hydro combustion in an aqueous ionic solution;

FIG. 3 is an isometric view of the retractable sheath of FIG. 2disclosing a fluid chamber that activates the acid-base throttle effectof oxy-hydro combustion in an aqueous ionic solution;

FIG. 4 is an illustration of a cordless oxy-hydro combustion probe ofthe invention, including gas storage containers (not depicted) and asource of electrical power (not depicted);

FIG. 5 is an illustration of a cordless oxy-hydro combustion probe ofthe invention, including gas storage containers (not depicted) and asource of electrical power (not depicted);

FIG. 6 is an illustration of a cordless oxy-hydro combustion probe ofthe invention, including gas storage containers (not depicted) and asource of electrical power (not depicted);

FIG. 7 is an illustration of a cordless oxy-hydro combustion probe ofthe invention, including gas storage containers not (depicted) and asource of electrical power (not depicted);

FIG. 8 is an illustration of a cordless oxy-hydro combustion probe ofthe invention utilizing a self-regulating automatic thermal quenchingportal system, including gas storage containers (not depicted) and asource of electrical power (not depicted);

FIG. 9 is an illustration of control automation of a cordless oxy-hydrocombustion probe of FIG. 8;

FIG. 10 is a top view of an electrosurgical probe providing conduits fordirecting the flow of elemental oxygen and hydrogen gases, a co-minglingplenum, and ignition electrode to ignite the oxy-hydro combustionprocess;

FIG. 11 is a side view of the electrosurgical probe of FIG. 10;

FIG. 12 is a graph depicting the acid-base throttle effect and itsrelation to salt concentration, energy imparted to the fluid, saltcrystal precipitate partial fraction, and electrical conduction;

FIG. 13 is a view of a porous electrode used to meter the flow ofoxygen, hydrogen or co-mingled enriching gases;

FIG. 14 is an illustration of a control mechanism for maintainingoptical spacing of the active electrode relative to tissue structuresand/or a translatable sheath;

FIG. 15 is a side illustration of a detachable positioning sheath; and

FIG. 16 is an illustration of a detachable positioning sheath.

DETAILED DESCRIPTION OF THE INVENTION

The invention disclosed herein provides electrosurgical devices thatoperate in conductive media, such as an ionic aqueous media. Theelectrosurgical devices employ combustion, and preferably oxygen andhydrogen (oxy-hydro) combustion, as a mechanism for tissue dissection,ablation, cutting, coagulation, modification, treatment and the like. Inone embodiment, an external source of oxygen or hydrogen, and preferablyboth, may be utilized. Electrical energy, such as a high frequencyvoltage difference, and preferably radiofrequency energy, can beemployed to initiate oxy-hydro combustion and, in the embodiments sorequiring, induce electrolysis of the media within which it functions orof the tissue to which it is applied to achieve the desired goals ofelectrosurgical treatment.

The equations of FIG. 1A illustrate the chemical equations that describethe overall oxy-hydro reaction, with associated acid-base shifts,resulting from hydrolysis of water and subsequent ignition of theresulting oxygen and hydrogen as disclosed herein. It is hypothesizedthat what has been traditionally thought of as the ordinary phenomenonof electrosurgery, namely “arcing”, “electron excitation”, “molecularfriction”, “vapor layer”, “plasma formation”, “plasma streamers”, or“popping”, may more properly be understood to be a result, in at leastsubstantial part, of oxy-hydro combustion occurring within biologicconstraints. The physiochemistry of the electrosurgical process ishypothesized to consist of an acid-base shift that governs the relativeavailability of the amount of water that can be consumed as part of ahydrolysis chemical reaction. The hydrolysis reaction is driven by thehigh frequency current flowing between active and return electrodes inboth the bi-polar and mono-polar modes of operation of electrosurgicalprobes. This oxy-hydro combustion theory accounts for all necessarychemical and energy constituents that are present as well as thephysical observations of light emission and heat generation during theuse of such devices. The physiochemical occurrences of electrosurgeryhave not previously been reconciled into a single accurate and cohesivetheory.

Chemical equations 10 generally govern the process herein disclosed,whereby the initial liberation of elemental oxygen and hydrogen gases 30occurs by means of electrolysis. Given that the underwaterelectrosurgical process occurs in a salt solution, either externallyapplied or that of the tissue or cell itself, such as a 0.9% by weightsaline solution, the true role of these elements should also bereconciled. The presence and true action of the salt, i.e. sodiumchloride (NaCl) for example, can be accounted for by means of equations10. The normal stoichiometry of the electrolysis reaction dictates thatif elemental gas separation is occurring, then the solute participantsmust join with the remaining solution components of water to form acomplementary acid-base pair. This pair is shown on the right-hand sideof the upper half of equations 10 as hydrochloric acid 15 and sodiumhydroxide 20 base pair. As is well known, hydrogen and oxygen gases 30can be co-mingled without spontaneous exothermic reaction. A smallamount of energy, such as RF energy 40, is required to overcome thenominally endothermic reaction and ignite the oxy-hydro combustion. Onceignited, the reaction will continue until all the reactants are consumedand reduced to the products shown on the right-hand side of the lowerhalf of equations 10.

The equations of FIG. 1B illustrate the effect of the acid-basethrottling reaction herein disclosed. The oxy-hydro combustion processdepicted is dynamic and occurs in a fixed fluid reservoir, whichnecessarily results in dynamically changing concentrations of salt ionsas a function of electrolytic conversion of water to elemental gas. Thisequation necessarily suggests that as the acid-base shift occurs in thereservoir, less and less water is available for hydrolysis. Thisphenomenon is seen in FIG. 1B where the acid-base pair is shown inincreased molar proportion to the normal stoichiometric quantity of basereactions 10. The reduction of available water for hydrolysis is evidentin the relationship 50 of oxygen and hydrogen gas to the acid-base pair.The finding is necessarily evident from the stoichiometry, namely thatinsufficient water is available given a fixed initial eight (8) moles ofwater, based on the finite reservoir of water, with increasing resultingmolar concentrations of acid and base as oxygen and hydrogen areliberated from the solution in a gaseous state, such as by bubbling outof solution. As fewer moles of oxygen and hydrogen gas are present afterhydrolysis as in FIG. 1B, the balancing portion of atoms account for thedynamic increase acid-base concentration.

The equations of FIG. 1C demonstrate a more general case of theoxy-hydro combustion reaction process in which the ionic salt isrepresented by variable 60, where X is any appropriate group I, period1-7 element of the periodic table. This generalized reaction illustrateshow hydronium and hydroxide ions can contribute to the same overallchemical reaction known as oxy-hydro combustion.

The equations of FIG. 1D demonstrate the more general case of theoxy-hydro combustion reaction process in which the ionic salt isrepresented by variables 61 of α, β, γ, and δ, wherein the molarquantities required for stoichiometric combustion are any value thatappropriately satisfies the oxidation reduction valence requirements forthe overall reaction. This generalized reaction case shows how oxygenand hydrogen requirements can vary and still result in the same overallchemical reaction known as oxy-hydro combustion.

The modes of oxy-hydro combustion operation described in FIG. 1A, FIG.1B and FIG. 1C depict theoretical stoichiometric reaction processesinduced by application of high frequency electromagnetic energy to asalt ion solution, including salt ion solutions typically found withinbiologic tissues themselves. The fundamental process is governed by therate of electrolysis in the initial dissociation of water into oxygenand hydrogen gas, as shown in equations 10.

Without wishing to be bound by theory, it is believed that the mechanismof action explaining operation of prior art electrosurgical devices iserroneous, and that an understanding and appreciation of the hereinhypothesized correct mechanism of action results in devices and methodsas further disclosed herein.

In prior art, it has been assumed that conventional bipolarelectrosurgical devices utilize excitation and relaxation of salt ionsresulting in photonic energy release such as through a plasma formation.The basis for such claims is that sufficient energy is imparted to thevaporized salt solution to provide electron shell excitation of thenative sodium ions. Upon relaxation of the excited electron, a photon isemitted (a foundational concept of quantum theory as originallydeveloped by Niels Bohr in 1913). However, the ionization energy permole of Na is 496 kJ as referenced in the CRC Handbook of Chemistry andPhysics, 72 ed., Lide, David R., CRC Press, 1991, pp. 210-211. Thisenergy is the equivalent to 496,000 Watt-seconds/mole. Even if onlyone-tenth of a mole of Na is present, a net energy of 49.6 kW-s/mole isneeded to ionize the sodium to form a plasma. This energy is far greaterthan the 200 to 1500 Watts of power provided by prior art conventionalelectrosurgical power supplies, methods, and devices.

Further, monopolar electrosurgical devices have been described as usinga “molecular friction” phenomenon to generate an “arc.” The implicitassumption of this paradigm is that the majority of the energy impartedby the wave/particle function of nominal waves created by theelectrosurgical power supply and device is absorbed at the naturalfrequency of the salt ions. A process called “ionic agitation” toproduce molecular friction, resulting from ions attempting to “follow”the changes in direction of alternating current, is used as one commondescription of the observed phenomenon as referenced in M. J. Medvecky,et al., Thermal Capsular Shrinkage Basic Science and Applications,Arthroscopy: The Journal of Arthroscopic and Related Surgery, 2001;17:624-635. However, ordinary microwave technology demonstrates thathigher frequencies are needed to excite water, including salt water, aswell as the ions normally contained within biologic tissue.Additionally, understanding how ions from a salt exist in solution makesit unlikely that the claimed excitations result in the observedphenomenon. A normal saline solution consists of sodium chloride (NaCl)salt dissolved in water, conventionally ˜0.9% NaCl by weight for normalsaline. Classical solute-solvent theory states that the salt (solute)will dissociate in water (solvent) to form NaOH and HCl in equilibrium.Thus the actual energy is not absorbed by a “salt” ion at all, butrather by the acid-base equilibrium ions in coexistence within thesolution media.

From these examples, it is hypothesized, again without wishing to bebound by theory, that many of processes heretofore described asresulting from a “plasma” actually are a result, at least in part, ofoxy-hydro combustion. The oxygen and hydrogen are created byelectrolysis, with concurrent ignition, all as a result of highfrequency, high voltage energy sources. The invention disclosed hereincorrectly explains the phenomenon heretofore described duringelectrosurgery observations as “arcing”, “electron excitation”,“molecular friction”, “vapor layer”, “plasma formation”, “plasmastreamers”, or “popping”. The understanding and appreciation of thisdisclosed mechanism of action enables further electrosurgical device andmethod embodiments that more accurately follow in vivo physiochemicalprocesses and open such embodiments to new applications not previouslyenvisioned for electrosurgical devices and methods as disclosedheretofore.

The modes of electrolysis and oxy-hydro combustion operation describedin FIG. 1A, FIG. 1B and FIG. 1C depict theoretical stoichiometricreaction processes induced by application of high frequencyelectromagnetic energy to a salt ion solution, including salt ionsolutions typically found within biologic tissues themselves. Thefundamental process is governed by the rate of electrolysis in theinitial dissociation of water into oxygen and hydrogen gas, as shown inequations 10. Based upon this understanding, methods and devices forelectrosurgery can be developed that utilize (1) one or (2) the other,or (3) both of the electrosurgical constituent reactions known aselectrolysis and oxy-hydro combustion as herein disclosed.

For example, oxy-hydro combustion can be utilized for therapeuticprocedures like cutting, ablation, coagulation, vaporization, and otherrelated procedures that are similar to those previously disclosed in theprior art. The oxy-hydro combustion reaction delivers the energyconfiguration necessary to cause these tissue effects and the hostresponses thereof as desired and described in those procedures.Electrosurgical methods and devices used for these types of procedures(see U.S. Pat. Nos. 5,669,904, 6,206,878, 6,213,999, 6,135,998,5,683,366, 5,697,882, 6,149,620, 6,241,723, 6,264,652, 6,322,549,6,306,134, 6,293,942, and other patents to similar effect) presumptivelyutilize this reaction, despite the lack of recognition in such patentsthat the occurrence of electrolysis and oxy-hydro combustion is at leasta primary effecter in these types of procedures (rather than plasma orrelated forms of Ionizing radiation). In essence, prior art methods anddevices have been developed to achieve specific and interrelatedtreatment goals without fully understanding the physiochemicaloccurrences of electrosurgery as practiced. An inherent risk in such asituation is the possibility that iatrogenic harm and complication mayoccur related to the use of such methods and devices. Most notably theseiatrogenic complications are due to the inability to fully contain theenergy application of electrosurgery to tissue based upon the limitedunderstanding of the physiochemical processes that are occurring.Unfortunately, since the use of such methods and devices have beenincreasing as electrosurgical techniques have become more popular andindications for use have been expanding, some practitioners andresearchers have called for the guarded use of electrosurgicaltechnology until further investigation can be completed. See, forexample, “Thermometric determination of cartilage matrix temperaturesduring thermal chondroplasty: comparison of bipolar and monopolarradiofrequency devices.” Arthroscopy. 2002 April; 18(4):339-46.

The treatment methods and devices of the prior art rely upon the commondenominator of tissue necrosis as the means to accomplish thesetreatment goals; and, this tissue effect is the main parameter employedto categorize prior art electrosurgery as a means to achieve tissuecutting, ablation, coagulation, vaporization, and the like. Mostpeer-reviewed studies have evaluated level of necrosis, depth ofnecrosis, or related parameters to quantify electrosurgical effects forthese types of treatment procedures as such evaluation are most relevantin those treatment settings. Tissue necrosis occurs to some degree inall methods in the prior art due to their desired goals of tissuecutting, ablation, coagulation, vaporization, and the like. Thisnecrosis is typified histologically by karyorrhexis or nuclear picnosisat one end of the spectrum and frank necrosis or vaporization at theother end followed by host responses directed to the specific level ofnecrosis induced by the manner of tissue treatment.

Electrolysis as the initial functional reaction of electrosurgery, onthe other hand, has not been explicitly recognized or exploited in theprior art for therapeutic procedures. The methods and devices developedin the prior art to achieve the treatment goals of cutting, ablation,coagulation, vaporization, and the like, have been generated without theknowledge of electrolysis as a relevant constituent part of theelectrosurgical physiochemical process. This circumstance furtherclarifies the motivation of prior art to limit methods and devices tocutting, ablation, coagulation, vaporization, and the like that requirethe higher energy configurations that induce oxy-hydro combustion. Basedupon this realization, methods and devices designed to provide oraugment the supply of the constituents of the oxy-hydro combustion asdisclosed herein can bypass the relative need of electrolysis fortherapeutic procedures designed to accomplish such related treatmentgoals as cutting, ablation, coagulation, and vaporization yet in a moreexpedient and efficient manner. One of the major motivations for thesemethods and devices, as herein, is to decrease tissue electrolysis forthese types of treatment procedures since electrolysis induced in tissueitself is very detrimental to tissue cellular structures. It induces notonly tissue necrosis quite dramatically but also transfers othersignificant collateral physiochemical effects that are not necessary andare additionally problematic for the treatment goals of cutting,ablation, coagulation, vaporization, and the like, as will be discussedbelow. These collateral effects often delay or impair healing responsesof the surrounding areas of tissue treatment, expanding the depth ofnecrosis as described witnessed in prior art electrosurgicalapplications and peer-reviewed assessments. The methods, devices andmeans as disclosed herein provide for limiting electrolysis-relateddetrimental tissue effects witnessed during the electrosurgicalprocedures of cutting, ablation, coagulation, vaporization, and the likethat are realized through the understanding of the physiochemicaloccurrences of electrosurgery. Tissue changes and responses thereof aremore fully recognized and characterized allowing additional novel usesfor the oxy-hydro combustion phenomenon. In one such embodiment, tissuecontact with the working electrode(s) of the instrument probe can beeliminated via the use of a translating sheath that can contain theconstituents of the relevant electrosurgical reactions and place theactive electrode(s) away from the tissue surface. This procedure asdisclosed herein benefits the tissue in that the location ofelectrolysis and oxy-hydro combustion occurrences is shifted from thatwithin the tissue itself (as contemplated and practiced in prior artsince the probe electrodes are used to contact the tissue to exert itseffects) to that within the surrounding fluid. This shift can be partialor complete based upon the desired tissue effects of electrolysis andoxy-hydro combustion at the treatment locale. In this way, tissueelectrolysis can be marginalized as a relevant occurrence in thecutting, ablation, coagulation, and vaporization treatment methods thatutilize oxy-hydro combustion.

Based upon the foregoing, the following is apparent: First, in thoseinstances where it is desirable to induce tissue cutting, ablation,coagulation, or vaporization by electrosurgical means (i.e. high energytissue necrosis and removal), the occurrence of electrolysis in any formmay be irrelevant to the procedure goals, and thus oxy-hydro combustionserves as the relevant effecter of the procedure. This may beconveniently done by means of the methods and devices provided herein,including by means of externally supplied oxygen and nitrogen, by meansof partially externally supplied combustion elements, such as by meansof a hydrogen-liberating electrode, or by means of electrolysis. Second,in those instances where oxy-hydro combustion is desired and tissueelectrolysis is not, such as when collateral tissue damage is to beavoided, the methods and devices of as provided herein can be employedwith oxy-hydro combustion as the effecter of the procedure. Third, inthose instances where tissue electrolysis is desired and oxy-hydrocombustion is not, i.e. a lower energy transfer to tissue is desired,the methods and devices disclosed herein can be employed. Fourth, inthose instances where the effects of electrosurgical electrolysis aredesired without tissue electrolysis or oxy-hydro combustion, the methodsand devices disclosed herein can be utilized.

It is thus hypothesized that current art electrosurgical processes,presumably through failure to recognize these processes as effectingtissue electrolysis and oxy-hydro combustion, have effectively beendesigned and implemented such that inducing various levels of tissuenecrosis in the form of cutting, ablation, coagulation, vaporization,and host responses thereof results. The methods and devices as disclosedherein can be employed to decrease tissue electrolysis and itsassociated detrimental collateral physiochemical effects.

In one embodiment of the invention, the devices and method of thisinvention include a means to deliver one or more gases required forcombustion to a surgical site, without the need to perform electrolysisto liberate hydrogen and/or oxygen for the combustion process. In onepreferred embodiment, both oxygen and hydrogen gases are provided forthe combustion process, with ignition through electrode means. The gasesmay be in a compressed form, and optionally are metered via throttlingvalves and mixing chambers. The gases, such as oxygen and hydrogen,delivered via a suitable conduit to an electrosurgical device. The gasesare delivered to the distal end of said device where they are ignitedusing a voltage source and an ignition device. The resulting combustionzone is sufficiently controllable to enable treatment of smallbiological structures and sufficiently scalable to permit treatment ofcomparatively large areas.

The devices of the invention described herein may be employed with anyof a wide variety of tissues, including without limitation any softtissue or hard tissue, or soft tissue-derived and bone-derived productsand/or materials. In the case of collagen tissues, the methods anddevices can further be employed to fuse, weld or otherwise join suchtissues such as for bone welding, vascular anastomosis, neurorraphy, andthe like. Further, as acid-base shifts affect cell membranepermeability, such changes can be harnessed for therapeutic measures, asdisclosed in U.S. patent application Ser. No. 10/486,739.

It may further be seen that certain embodiments of the inventiondescribed herein may be employed in applications where prior artconventional monopolar devices are employed, such as in a non-conductiveaqueous media of some endoscopy fluids. Even where themacro-environment, such as endoscopy fluids, is non-conductive, themicro-environment, in proximity to the electrodes and devices hereafterdescribed and the biological tissues to be modified, is necessarilyconductive. Thus the methods and devices described herein may, with suchmodifications as are required and will be apparent to one of skill inthe art, be employed in applications where prior art conventionalmonopolar devices are now employed. Similarly, the methods and devicesdescribed herein may be employed in applications where prior artconventional bipolar devices are employed, such as environments whereina conventional conductive aqueous media is employed. Further, themethods and devices described herein may be employed in applications oftraditional open surgical procedures, i.e. in ambient air (versusendoscopic procedures), with the host biologic tissue itself serving asthe fluid reservoir or fluid environment.

The devices of this invention can be employed with a variety ofsolutions, including 0.9% NaCl, 0.9% KCl, H₂SO₄, HCl, distilled H₂O, anda glycine solution, and a variety of state parameters, including variedpH and temperature. Further, the devices and methods of this inventionhave been employed without solutions in the macro sense, and been use in“ambient” air conditions of hydrated and normal biologic tissue. Inaddition, a variety of RF energy settings have been employed, such asthe embodiment of 150-2000 Volts peak to peak with a range of powersettings between 5 and 500 Watts. Based on analysis of varioussolutions, states, and energy profile applications, the general equationof FIG. 1C was validated, and data obtained for the graph of FIG. 5.Although the energy input required to initiate and/or sustain a plasmamarkedly exceeds these levels (or any levels contemplated forelectrosurgical application), even for the most favorable plasmagenerating conditions (refer to above ionization discussion fortypically encountered constituents of a biologic system duringelectrosurgery), the transition from electrolysis and combustion to thatof plasma formation based upon energy input has not been determined. Itis anticipated that as energy level is increased, significantlysurpassing the ionization potentials of the constituents of a biologicsystem, electrolysis and combustion would yield to plasma formation;however, this transition point far exceeds the levels of energy that anorganism can withstand and is not contemplated for electrosurgery due tothe significant iatrogenic injury that would be induced. The energyconfigurations typically employed in and contemplated forelectrosurgery, and those that we have verified as discussed above,provide sufficient energy to initiate and sustain the electrolysis andcombustion reactions as disclosed in U.S. patent application Ser. No.10/486,739, allowing for the use of such physiochemical reactions fortherapeutic means as disclosed in U.S. patent application Ser. No.10/486,739.

The devices described in FIGS. 4 through 9 do not employ electrolysis toproduce hydrogen and gas with concurrent ignition of the oxy-hydrogenflame at the point of electrolysis. Rather, in one preferred embodimentthese devices employ gas canisters, which may be miniature canistersdisposed within the handle of the device. At least one of thesecanisters contains oxygen and at least one other canister contains a gasthat may be employed in combustion; hydrogen is a preferred gas, butother gases may be employed, including preferably gases wherein one ormore carbon atoms are present, such as methane, acetylene or othergases. In an alternative embodiment, oxygen and hydrogen may be storedwithin a confined matrix material. In yet another embodiment, thedevices may include a container for electrolysis, such that within thehandle or another portion of the device there is contained a volume ofliquid, such as saline solution, and one or more electrodes forelectrolysis, the electrolysis producing oxygen and hydrogen, whichoxygen and hydrogen transits the conduits provided and is ignited asprovided in the following description. Depending on the powerconsumption characteristics of the electrode(s) employed forelectrolysis, it may be necessary to employ a wire connecting thedevice(s) to a source of power sufficient for the intended purpose.

The devices described in FIGS. 4 through 9 further contain a source ofelectrical power, such as a battery, which may be a rechargeablebattery, a fuel cell, or the like, producing sufficient power foroperation of the electronic circuitry, if provided, and for ignition ofthe oxy-hydrogen mixture. In one embodiment, a fuel cell may be employedto produce electrical power. A proton exchange membrane type of fuelcell is employed, wherein hydrogen and optionally also oxygen isprovided by means of one or more canisters, which canisters are alsopreferentially further employed for oxy-hydrogen combustion. Oxygen mayalternatively be obtained from the atmosphere. Sufficient separate fuelcells are combined to form a fuel-cell stack producing the voltagerequired for the specific application.

FIGS. 4 through 6 illustrate the use of a cordless oxy-hydro combustionprobe useful for cutting all forms of tissue, including hard bonystructures, without the necessary need for electrolysis of the media inwhich the probe functions and without the induction of internal tissueelectrolysis, which is detrimental to tissue viability. Thus thesedevices may be employed for ablation, cutting, coagulation and/orvaporization of tissues. Independently isolated flow conduits 275, 276are provided within primary lumen 140 separated by wall 270 and suppliedto a fluid acceleration converging nozzle 151 whereby the independentgas constituents are accelerated to a turbulent state. As set forthabove, the source(s) of gases are canisters, matrix material whichreleases gases, a hydrolysis chamber or the like. In a preferredembodiment, the source of gas is sufficiently small to be containedwithin the handle or adjacent portions of the device, such that thedevice can readily be held in one hand by the surgeon withoutconnection, by wires or tubes, to any external structure. Upon exitingthe independent conduits explosion protection is provided in the form ofa spark or flame arrester 280 to prevent combustion propagation into thedevice. The co-mingled gases are ignited via electrode 70 (herefunctioning as an external igniter) to produce the oxy-hydrogen flamethat is used to perform tissue operations. Probe tip 150 is manufacturedso as to have a sharp leading edge as shown near the fluid flow exitportal for ancillary use as a mechanical sharp cutting device inaddition to thermal and ablative characteristics normally exhibited byoxy-hydro tools.

FIG. 8 illustrates a cordless oxy-hydro combustion device utilizingself-regulating automatic thermal quenching portal system 272. Thisportal system provides a means for the induction of surrounding fluidmedia at proportional rates to oxygen and hydrogen gas flow to maintaindesired maximum flame temperatures at exit/ignition portal 69. Thisfluid induction is metered into the independent gas flow streams, whichare separated by wall 270. This fluid induction is created by means ofinternal venturi section 142 providing gas acceleration which createssub-ambient pressure at portal 272 inlets and subsequently drawingsurrounding fluid into gas stream 269. This venturi section 142 may beprovided at a variety of specified angles relative to primary lumen 140.Portal 272 provides calibrated orifice entry points into gas stream 269at known volumetric flow rates, providing proportional mass-flow whichacts as a heat sink within the oxy-hydro combustion reaction accordingto the first law of thermodynamics (q=m·Cp·ΔT, where Cp is defined asthe latent heat of vaporization for the surrounding fluid). The massflow rate of surrounding fluid is calibrated by means of said entryportals to provide sufficient combustion quenching heat capacity tomaintain safe and effective operational thermal discharge levels ofexit/ignition portal 69. This ignition is created by electrode 70 (herefunctioning as an energy input filament). This ignition system (69, 70)is disposed within the distal insulating tip assembly 150, which may bemade detachable from the venturi induction portion 142. The spark orflame arrester 280 acts as an additional fluid mixer/atomizer to ensureeven dispersion of entrained surrounding fluid thereby providingadditional means of evenly controlled combustion zone thermal variation.

FIG. 9 illustrates the control automation to a cordless oxy-hydrocombustion probe. Variable sensor 391 provides means for detectingcombustion zone temperature and provides feedback signal to temperaturecontroller 520. The temperature controller is configured as part of anoverall fluid manifold gas quenching system, comprised of differentialsignal output controller 500, which supplies independent, proportionalcontrol signal to flow control valves 510 governing proportional flow ofinert quench fluids to the primary oxygen and hydrogen gas flow streams.The proportional flows provide thermal combustion control atexit/ignition portal 69. Proportionality of the temperature controller520 is governed by user-defined set points within the engineered limitspan of the controller 520. The general function of the temperaturecontroller 520 is to provide additional quench gas when the user definedset point is positioned for lower temperatures and to decrease thequench gas flow when the user defined set point is positioned for highertemperatures. The controller 520 has a 4-20 mA output proportioned tothe combined released heat of reaction including heat lost due toabsorption by inert non-reacting quench gases at the desired set pointdialed in by the user. The structures defined by 70, 140, 142, 150, 270,272, and 280 serve the same functions as in FIG. 8.

FIG. 14 illustrates the automated control which provides a means formaintaining the optimal spacing of the active electrode 70, disposeddistal from the primary lumen 140 which is simultaneously acting as thereturn electrode, from tissue structures being treated. Here too it isintended that the device be employed only so as to provide electrolysisonly of the media or other interfacing agent, without electrolysis oftissues of the patient to be treated. Thus the design of the device ofFIG. 14 is such that induction of tissue electrolysis by contact of theactive electrode to the tissue is avoided. Further, combustion is itselflimited, depending on the rate of electrolysis, and the therapeuticaffect is largely a result of electrolysis of the media adjacent to, butnot in contact with, tissues to be treated. Actuating arm 531, which inturn is driven by electric positioning motor 530, actuates translatablesheath 80. Translatable sheath thus can extend the insulating propertiesof insulator 150 beyond the profile or position of the active electrode70, providing means to create a temporary localized chamber when thetranslatable sheath 80 is extended and brought into contact with tissue.Fluid field sensor 391 provides primary control variable feedback todifferential controller 501 as analog input and is output via flip-flopAND conversion to a digital control signal for use byapplication-specific integrated circuitry logic controller 511, such asan FPGA, MOSFET, or similar intermediate digital logic gate controllingarray. Flash RAM, and additional high level input/output governance, iscontrolled by CPU 521, utilizing software governed database lookuptechniques, such as those commonly known in C+ or C++ programming code,to provide dual proportional output via Primary RF OutputController/Generator 522; and further and optionally also to ElectronicPositioning Controller 523 for simultaneous balanced positioning oftranslatable sheath 80 coupled to matched power setting throughcontroller 522, providing the primary controlling input to match userset-point according to primary control variable known characteristicscorrelation to desired set point. Electrical power may be provided bywires connected to a suitable source of power, which may be one or moresources of power, such as a high voltage source for operation of theactive electrode and a lower voltage source for operation of thecircuits provided, or may alternatively be by means of a fuel cell orany other suitable source of electrical power.

Thus the device of FIG. 14 provides, in one embodiment, for the use of“feedback loop” control algorithms to govern the electrical motors orother actuating means to position or move the insulating sheath member,wherein one input for such control algorithms includes either the degreeor rate of electrolysis (where the device provides for electrolysis) orthe combustion rate of the oxygen and hydrogen (or other hydrocarbonfuel). Either the degree or rate of electrolysis, or alternatively thecombustion rate, or both, may be set by a programmable setting, oralternatively may be a function of a third parameter measured by meansof a sensor, such as gas production, temperature, etc.

FIG. 7 illustrates the use of a fixed electrode insulator geometryoptimized for use as an electrosurgical probe. In this device,electrolysis is induced by the electrode, with concomitant ignition ofthe hydrogen and oxygen gases. It is intended that the device beemployed only so as to provide electrolysis only of the media or otherinterfacing agent, without electrolysis of tissues of the patient to betreated. Thus the design of the device of FIG. 7 is such that inductionof tissue electrolysis by contact of the active electrode to the tissueis avoided. A second electrode, or return electrode, is provided and maybe disposed on the probe, but is not depicted. Further, combustion isitself limited, depending on the rate of electrolysis, and thetherapeutic affect is largely a result of electrolysis of the mediaadjacent to, but not in contact with, tissues to be treated. Insulator150 is configured distal of primary lumen 140 (which simultaneously actsas the return electrode) whose surface area is limited by insulation 180to provide means to maintain fixed tissue separation from activeelectrode 70. This spacing creates a reaction chamber for theelectrosurgical reactions and creates a chamber between active electrode70 and the leading edge of insulator 150 when insulator 150 is incontact with tissue. The leading edge of insulator 150 is provided witha semi-sharp or roughened edge to prevent inadvertent tissue “bulging”which may cause tissue contact with active electrode 70. This reactionchamber is typically filled initially with the fluid of theelectrosurgical environment when in contact with adjunct tissuestructures providing localization for the electrosurgical reactions toinduce therapeutic benefits. The elimination of tissue contact with theactive electrode eliminates the presence of internal tissue electrolysiswhich is detrimental to tissue viability. In the device of FIG. 7,either AC or DC current may be employed, and an unequal current densitybetween a first electrode and second electrode, such as the activeelectrode and a return electrode, is not required. Thus the device ofFIG. 7 may effectively operate with equal current densities between afirst electrode and second electrode. Similarly, the device of FIG. 7may operate at lower energy levels and further lower current densitiesthan that required for prior art electrosurgical devices, such energylevels and current densities being only such as are required forelectrolysis of an aqueous medium into oxygen and hydrogen and toinitiate combustion of the oxygen and hydrogen so generated.

FIGS. 15 and 16 illustrate a detachable positioning sheath. The devicesof FIGS. 15 and 16, and similar devices, may be employed with prior artconventional RF electrosurgical devices or probes. Use of such artconventional devices results in tissue electrolysis at points where theelectrode(s) contact the tissue, resulting in tissue necrosis anddelayed wound healing. The sheaths of FIGS. 15 and 16, and similardevices, may be employed with such art conventional RF electrosurgicaldevices or probes, and result in positioning of the active electrodesome distance from the tissue to be treated. In an appropriate aqueousmedia, the devices will induce electrolysis and, depending on the rateand volume of oxygen and hydrogen so produced, combustion of such gases.Thus energy transfer to the tissues is by means of an interfacing agent,such as a saline solution, with attendant reduced tissue necrosis anddamage. Uses and applications of such therapeutic means are disclosed inU.S. patent application Ser. No. 10/486,739, incorporated here byreference. With respect to FIGS. 15 and 16, rigid cylindrical sheath 80,may be provided with perforations of various configurations withoutaltering the fundamental principle of its function, and provides knownspacing between tissue structures and electrosurgical probe activeelectrodes 70. This rigid sheath portion is positioned co-cylindricallyon any electrosurgical probe that is not sheath enabled, therebyproviding accurate spacing by means of demarcations 79. Flexiblepolymeric fixation sleeve 81 is unrolled onto primary lumen members ofnon-sheath enabled probes to provide fixation of the rigid sheathrelative to probe active electrode position. Preferably the sleeve 81 ismade from a translucent, and more preferably transparent, polymericmaterial. The sheath of FIGS. 15 and 16 can be repositionedintra-operatively through the use of forceps or manual unrolling torelocate rigid sheath portion 80. Rigid and flexible sheath portions maybe adhesively bonded or ultra-sonically welded together to preventrelative translation and ensure accurate positioning throughout theentirety of procedural operations. Advantageously, the demarcations 79provide distance graduations for accurate positioning of the sheath at aprocedure-specific distance prior to insertion of the RF electrosurgicaldevices or probe with a sheath of this invention, such that adequateseparation may be maintained between the probe or device end, andspecifically an electrode thereof, and tissue to be treated.

FIG. 2 is a view of a preferred embodiment of an acid-base throttlesheath probe used in the underwater, cellular and biologicelectrosurgical environment. Translating sheath 80 is employed to createan acid-base trapping zone and thereby harness the acid-base“throttling” effect of lowering the available moles of electrolyzedoxy-hydrogen gas, thereby reducing the net heat of reaction in theoxy-hydro combustion. Translating sheath 80 extends itself beyond themost distal portion of active electrode 70 to form a plenum chamberwherein acid-base pairs are allowed to collect and decrease thereactants of oxy-hydro combustion. Current flows between activeelectrode 70 and return electrode 140 to complete the electricalcircuit. Sheath 80 can be selectively positioned by using slidingratcheting finger switch 120 via coupler guide stanchion 110 andpush-rod 100 to set the desired quantity of acid-base entrapment andtune the rate of reaction observed at active electrode 70. Activeelectrode lead wire 75 is constructed to have sufficient slack withinthe probe body that translation of active electrode 70 is notconstrained by connected lead wire 75. Sheath return spring 90 istensioned by translation of push rod 100 as sheath 80 is extended to itsmost distal position, and is retained by finger switch ratchetingmechanism 120. When released, sheath 80 is pulled by return spring 90into its normally proximal position.

FIG. 3 illustrates another view of a preferred embodiment of theacid-base throttling sheath. In this view acid-base throttle sheathmechanism 80 is in the distally extended position. Freedom of travel isshown by translation direction arrows 170. The electrical circuit iscompleted between active electrode 70 and return electrode 140. Both theactive and return electrodes are conductively isolated from each otherusing thermal and electrical insulator 150 which may preferably beconstructed of a ceramic or high temperature polymer. The remaining areaof the return electrode is insulated by insulating sheath 180. Asdepicted, the energy applied to the probe is only sufficient to generateelectrolysis and is fully consumed by said reaction, Insufficient excessenergy exists to ignite the co-mingling oxy-hydrogen gases and thus onlythe products of the first of reactions 10 are created. During typicalapplication of low-level RF energy acid-base pair density streak lines160 are plainly visible to the naked eye; these are byproducts of theelectrolysis reactions known to govern the overall process.

The translating sheath 80 may be cylindrical, as depicted, or may beconical, or may alternatively have a conical or cone tip. In this way,the size of the probe may be reduced, and the shape or configuration ofthe electrodes and sheath may be such as to direct energy in a desiredpattern or manner, so as to provide maximal energy delivery to adiscrete area to be treated, while minimizing injury to adjacenttissues. Similarly, in this way energy may be directed to the area to betreated without the probes or electrodes actually contacting such area.

In the operation of the preferred embodiment of FIGS. 2 and 3 theoxy-hydro combustion process is mechanically adjusted to suit thedesired intensity of operation. Active electrode 70 generates theoxy-hydro combustion reaction, while translating sheath 80 can bepositioned to create a convection trap for acid-base pairs 160 generatedas part of the oxy-hydro combustion reaction process. Increasing theconcentration of the acid-base pairs reduces the net available oxygenand hydrogen gases that can be generated by the electrolysis reaction.This, in turn, leads to a decreased intensity of the overall reaction.This effect is defined herein as the acid-base throttling effect on theoxy-hydro combustion reaction process. The translation of sheath 80alters the conducted electrical pathway of the RF energy. The sheath,when constructed of a non-metallic substance, does not alter thetransmission pathway. By positioning the sheath using ratcheting fingerslide 120, coupler guide stanchion 110 and push-rod 100 in combinationthe oxy-hydro combustion reaction can be trimmed to the most desirablelevel of intensity. Additionally, in surgical modes of operation whereno tissue contact is desired the throttling sheath can be used to fixthe distance to the tissue and provide a consistent tissue treatmentbenchmark distance. When combined with manipulation of delivered powerto the active electrode, a precise control of both the oxy-hydrocombustion reaction and the surgical process can thus be achieved.

FIGS. 10 and 11 depict a preferred embodiment wherein independent gasflow lumens are provided for the delivery of elemental gases to theprobe tip. In this embodiment an electrosurgical oxy-hydro probeprovides means for independent delivery of elemental oxygen and hydrogengas to the probe distal tip reaction zone. Elemental gases arepressure-driven through gas transmission lumen sections 275 separated bygas conduit wall section 270 to prevent premature co-mingling of theelemental gases. Upon exit from the lumen sections the gases are mixedin plenum chamber 260 to facilitate combustion reaction process. Thegases are then accelerated through converging nozzle section 250 toenhance dynamic pressure, thereby driving the oxy-hydrogen gas throughspark or flame arrester 280. The gas is then channeled upward throughinsulator 150 toward active electrode 70 to initiate the oxy-hydrocombustion reaction process. While an electrode is shown for initiatingthe oxy-hydrogen gas combustion, it is to be understood that theoxy-hydrogen gas combustion initiation may be from any of a variety ofmeans, such as an electrical spark, mechanical spark, thermal energytransfer and the like. In one particularly preferred embodiment, apiezoelectric gas ignitor may be employed, which may be mechanically orelectrically actuated, and which provides a high voltage spark based onthe impact of a hammer, such as a spring-driven hammer, on apiezoelectric ceramic substrate. In the case in which an electrode isemployed, the voltage and current can be any suitable voltage andcurrent that will initiate a combustion reaction, and the source ofpower may be either DC or AC. It is to be understood that advantageous,as opposed to prior art electrosurgical devices, the devices describedherein do not require an unequal current density between a firstelectrode and second electrode, and may effectively operate with equalcurrent densities. Similarly, lower energy levels and lower currentdensities are required than with prior art electrosurgical devices, suchenergy levels and current densities being only such as are required toinitiate combustion of oxygen and hydrogen.

In the embodiment of FIGS. 10 and 11 the need for an electricallyconducting irrigant is completely eliminated. FIG. 11 illustrates theseparation of the electrical circuit power delivery conduction portionof the probe in isolated electrical channel lumen 141. Active electrodelead wiring traverses the lumen length to the distal portion wherein itis electrically connected to active electrode 70 and can complete atransmission circuit via electromagnetic transmission field lines 195across insulator portion 150 to return electrode 140. Oxy-hydrocombustion zone 300 is created by the ignition of the co-mingled gasesbeing forced from the electrosurgical probe distal tip under fluidpressure. The rate of reaction can be governed by metering of the flowrate of the individual elemental gases or by “starvation” of eitherelemental gas to run the reaction sub-stoichiometrically “lean” or“rich”, which will alter the net heat of reaction according to normalprinciples of combustion reaction chemistry.

The operation of this embodiment illustrates how the need for a liquidirrigant medium can be completely eliminated. Pressurized elementaloxygen gas and hydrogen gas are independently delivered to probe tipinsulator 150 via isolated lumen section 275 and after mixing areignited by heat generated at active electrode 70 from solid/fluidinterface transmission wave generation heating. The intensely hot flamegenerated can be used for a variety of purposes in a surgical setting.Additional advantages in this specific mode of operation become evident.The power needed to ignite the co-mingling oxy-hydrogen gas mixture isreduced because the conducted portion of the energy needed toelectrolyze is now no longer necessary. Only that portion of the energythat provides heating to the active electrode sufficient to ignite themixture is necessary to sustain the combustion. FIG. 11 illustrates usesin conjunction with a fluid irrigant that provides further enhancingcapability to the oxy-hydro combustion reaction process. In many caseshaving intense heat sources within the human body is undesirable, anduse of an irrigant can provide multi-faceted additional advantages, themost apparent of which is as a quenching media to reduce collateral heattransfer to healthy tissue structures. Such an irrigant is preferablycomposed of acid buffering agents that form a solution resistant tochange in pH when either acid or base is added, such as from the naturalprocess of oxy-hydro combustion.

FIG. 12 depicts the general energy absorption curve for the electrolysisand ignition of the oxy-hydro combustion reaction process. The curvesdepicted show the multi-dimensional aspects of the immersed environmentand how they affect the overall combustion process. It is important tounderstand that the net energy consumption of the entire processconsists of two distinct components of RF energy, conduction andtransmission. Conducted energy 320 is consumed in the molecular electrontransfer between ions in solution. Transmitted energy 310 involves theelectromagnetic wave function that is typically involved with radio-wavetransmission. Both elements are present in ambient air, underwater,cellular, and biologic electrosurgery and contribute separate anddiscrete energy functions to the overall process. As shown in FIG. 12the mode of energy consumed is dependent on the relative concentrationof salt ion in solution. As the salt ion concentration approaches zerothe bulk of the energy is consumed through conduction as pure water isonly moderately conductive. Some transmission 310 actually occurs at allstates and is therefore shown as a smaller portion of the overall energyconsumed. As salt ion concentration increases the solution resistivitydrops and the amount of energy consumed through conduction 320 alsodrops. Sufficient resistivity of the solution media remains that heatingtakes place as part of the conduction process, but the active electrodebeing heated by its own metallic resistance at the liquid-metalinterface delivers the majority of the heat generated prior to ignitionof oxy-hydro combustion reaction. As the salt ion concentrationcontinues to increase, conduction resistivity continues to drop until arelative minimum of conduction resistivity 340 is achieved. At thispoint in oxy-hydro combustion energy absorption process curve 330 themajority of the energy consumed is through transmission 310. In allcases the curve defines the total energy input for which oxy-hydrocombustion ignition can be achieved. However, at the optimum salt ionconcentration point 340 the minimum amount of input energy is requiredto both electrolyze the solution and ignite the oxy-hydro combustionreaction.

If the salt ion concentration is increased further still, while holdingthe solution temperature constant, a partial fraction of solid salt ionwill co-exist as a suspension, the overall solution having reachedsaturation limit 370 for the given temperature. Curve portion 360illustrates the energy absorption required for oxy-hydro combustionignition as the partial fraction of salt ion is increased beyondsaturation limit 370 for the solution. As the salt ion concentration isincreased beyond saturation limit 370 along curve 360, both conductionand transmission resistivity are generally increased and the net energyrequired to achieve oxy-hydro combustion ignition is also increased.Curve 350 illustrated the shift in solubility created by increasingsolution temperature. Temperature rise in solvent is known to increasesolute capacity; this condition is commonly referred to as“super-saturation.” As the solution is heated, whether artificially orpurely by conducted heating from the active electrode, the energyrequired for oxy-hydro combustion is increased. From equations 10, itcan be seen that this is a result of greater concentration of salt ionfraction in the equilibrium state of acid-base pairs, which reduce thenet amount of water that can be electrolyzed into oxygen and hydrogengases. This specific condition is an artifact of a finite reservoir. Inmany surgical situations, as the fluid is in constant flow there is noexcessive buildup of acid-base pairs, since they are “flushed” away inthe flowing solution.

It can be appreciated from the chart in FIG. 12 that the acid-basethrottle effect can be overcome through the addition of RF energy as theconcentration of acid-base in solution rises. This is most advantageousin understanding why maintaining an optimum flow throughout the surgicalfield proves beneficial in electrosurgery. Too much flow and the heatedbuoyant gas escapes more rapidly than it can be combusted and becomesuseless to the surgical process. On the other extreme too little or noflow leads to excessive heating and build-up of acid-base that can havedeleterious tissue effects if left to accumulate for an extended period,including tissue and nerve damage or necrosis. The graph reveals thatthe solution temperature will have an indirect performance effect inallowing probe operations that vary widely from the optimum energyminima of concentration point 340.

FIG. 13 is a view of an embodiment wherein the active electrode includesa porous gas-liberating alloy. Elemental gas is delivered under positivepressure to active electrode 390 and forced through pores in theconductor. The enriching gas stream exits in diffuse gas stream 380 andenters the oxy-hydro combustion zone. Electromagnetic energy issufficiently imparted to the combustion zone to liberate elemental gasfrom the electrode alloy and ignite the enriched co-mingled mixture. Theelectromagnetic energy is delivered in transmission from activeelectrode 390 to return electrode 140, which is both thermally andelectrically insulated by insulator 150. Insulator 150 can preferably bemade from high temperature refractory ceramics or ceramic alloys.Elemental diffuse gas stream 380 is comprised of molecular hydrogen gas,molecular oxygen gas, or co-mingled oxygen and hydrogen gases to enrichthe oxy-hydro combustion zone.

In mode of operation of the device of FIG. 13, several of theindependent elements have been combined into a configuration of anelectrosurgical probe including porous active electrode 390, which maybut need not include a gas-liberating alloy, to enhance the oxy-hydrocombustion reaction process. Probe activation is enhanced by forcingelemental gas 380 through the pores of active electrode 390 into theoxy-hydro combustion zone for either quenching or maximizing heat of theoxy-hydro combustion reaction. The pores of active electrode 390 allowmulti-variate functions, including metering, mixing and directing theelemental enriching gases to the combustion zone. This embodimentprovides improved fluid dynamics at the surface of active electrode 390,including a laminar flow of the ejecting gas or gases, more evendistribution of the gas or gases and rapid thermal quenchcharacteristics. When operated in underwater, cellular and biologicsurgical environments the embodiment of FIG. 6 provides means forimproving the combustion zone dynamic volume by preventing pressurefield variations from forcing the collapse of the gas volume andquenching the electrode, thereby preventing oxy-hydro combustion. Bysupplying a uniform gas field immediately above the active electrode thegas volume is created as much by the flowing of the pressurized gas asby the electrolysis of the salt ion solution. This lowers the net powerrequired to achieve ignition of the gas mixture and provides means foroperating at much lower power levels, until a spike of energy is appliedwhereupon a pulse of oxy-hydrogen gas is supplied to active electrode390, creating conditions for an oxy-hydro combustion reaction cascade.From this description it will become apparent to those skilled in theart that many dynamic controls can be used to govern the flow of gas inconcert with the power output delivered to the active electrode toachieve novel effects in the oxy-hydro combustion zone.

It is to be understood that any of the devices as described above mayemploy a fuel cell to produce electrical power. In one preferredembodiment, a proton exchange membrane type of fuel cell is employed,wherein hydrogen and optionally also oxygen is provided by means of oneor more canisters, which canisters are optionally further employed foroxy-hydrogen combustion. It is to be understood that if the deviceemploys an active electrode, such that electrolysis and combustion areboth simultaneously induced, that excess hydrogen so produced may beemployed, in whole or in part, for such fuel cells, or alternativelyother sources of hydrogen, such as a storage canister, may be employed.Oxygen may alternatively be obtained from the atmosphere. Sufficientseparate fuel cells are combined to form a fuel-cell stack producing thevoltage required for the specific application.

The preceding devices can be varied by substituting the generically orspecifically described components and/or structures of this inventionfor those used in the preceding devices.

Although the invention has been described in detail with particularreference to these preferred embodiments, other embodiments can achievethe same results. Variations and modifications of the present inventionwill be obvious to those skilled in the art and it is intended to coverin the appended claims all such modifications and equivalents. Theentire disclosures of all references, applications, patents, andpublications cited above are hereby incorporated by reference.

1. A movable sheath adapted for use with a radiofrequency (RF)electrosurgical probe, comprising: a generally cylindrical plenum withan open first end and an open second end and of a diameter such that theopen second end may be co-axially placed over the electrode end of an RFelectrical probe, whereby the open first end extends beyond theelectrode end of the RF electrical probe; and a flexible polymericfixation sleeve for securing the position of the RF electrosurgicalprobe within the generally cylindrical plenum wherein the generallycylindrical plenum further comprises a plurality of perforations.
 2. Thesheath of claim 1 wherein the flexible polymeric fixation sleeve isfixed to the generally cylindrical plenum.
 3. A movable sheath adaptedfor use with a radiofrequency (RF) electrosurgical probe, comprising: agenerally cylindrical plenum with an open first end and an open secondend and of a diameter such that the open second end may be co-axiallyplaced over the electrode end of an RF electrical probe, whereby theopen first end extends beyond the electrode end of the RF electricalprobe; and a flexible polymeric fixation sleeve for securing theposition of the generally cylindrical plenum to the RF electrosurgicalprobe wherein the movable sheath comprises a plurality of demarcationsfor determining the position of the movable sheath with respect to theelectrode end of the RF electrical probe.